Password Strength Checker
Type a password to see an estimate of its entropy and how long guessing it would take. It never leaves your browser.
How it works
The estimate is length x log2(character pool): the pool grows when you mix lowercase, uppercase, digits and symbols. It then subtracts for easy patterns: very common passwords, repeated characters, keyboard runs like qwerty and sequences like 1234. Crack time assumes an attacker with a fast offline setup making 10 billion guesses per second against a weakly hashed password, so it is a rough guide, not a guarantee.
Length beats complexity. A random 4-word passphrase of 20+ characters is stronger and easier to remember than P@ssw0rd!. Use a password manager and never reuse passwords.
Frequently asked questions
Is it safe to type my real password here?
The check runs entirely in your browser and nothing is sent anywhere. Still, as a habit, test a similar password rather than one you use on important accounts.
What makes a password strong?
Length and unpredictability. 16 or more random characters, or a long passphrase of unrelated words, is far stronger than a short complex one.
Why does 'P@ssw0rd!' score badly?
Substituting symbols for letters is a well-known pattern that cracking tools try first, so it adds little real strength.